The structure of skis generally comprises a solid or hollow core and bearing elements arranged above and below this core which can be produced in one or two layers, for example from a glass fiber fabric impregnated with epoxy resin which may possibly be combined with a metallic blade made of aluminum or aluminum alloy of the Zicral 7075 type.
Skis provided with lateral reinforcements are also in existence. Thus, U.S. Pat. No. 4,093,268 relates to a ski in which a glass fiber reinforcement is arranged between a side element and the core and extends vertically between a lower edge and an upper edge. A similar structure is illustrated in U.S. Pat. No. 3,967,992.
More recently, U.S. Pat. No. 4,455,037 has described a structure in which a metallic reinforcing blade is interposed between the side elements forming the lateral faces of the ski and a wooden core, these reinforcing blades extending between a lower bearing layer and upper edges.
The production of skis having a tubular metallic framework has also been proposed, as described in the second addition FR-A No. 84,816 to FR-A No. 1,276,744, as well as in U.S. Pat. No. 3,208,761, in which the upper corners of the ski are constituted by the metal of the tubular structure. This design is quite different from that of skis formed from distinct elements assembled round a central core, since the tubular structure gives the ski all its mechanical properties. Such solutions pose extremely complex technological problems because the tubular structure is produced by menas of shaped sections. Now the cross-section of a ski varies constantly. This is why almost all skis are produced by means of layers arranged round a central core, either by dry means, that is to say by means of pre-fabricated layers assembled by sticking, or by moist means, or by polymerizing impregnating resins at the same time as the various constituents of the ski are stuck, or by injecting certain structural elements, in particular the core, after having pre-assembled the elements of the structure surrounding it in a mold.
The upper surface of the ski which also constitutes the decorative portion thereof is particularly exposed to harmful external factors which may damage it by causing obvious wear of the ski which devalues it even if its mechanical properties do not suffer. This is why a large number of skis have not only lower edges intended to improve the grip of the ski on the snow or the ice but also upper edges intended to protect the decorative portion, in particular during cross-over of the skis. With regard to manufacture of the ski, these upper edges increase the number of parts to be assembled and they complicate the structure of the ski because, like the lower edges, they have to be fixed in the ski.